This invention relates to optical cable splices for various optical communication applications and, more specifically, to a reconfigurable optical cable splice which allows connections to an optical cable or module to be reconfigured so as to use spare fibers in the event of damage to optical fibers originally in use.
Known methods for repair of optical links in vehicles, such as aircraft, at the time of damage include removal and replacement of the damaged cable, repair of the damaged cable, and linking in a spare fiber to skirt the damage followed by repair or replacement of the damaged cable at a convenient time. The first method is difficult to perform on vehicles where the cables often run in inaccessible locations. It also requires having on hand a replacement cable, a situation that is rarely the case in extreme conditions such as in battle.
As to repair of optical fiber cables, special tools and training is currently required, and it is difficult to do properly except in clean hanger conditions. It is also time consuming, even in the laboratory environment, wherein the repair process usually requires 30 minutes per optic link to be repaired. The use of ribbon cables can speed the repair time per fiber. However, even those methods can be difficult to apply in the field because of the need to directly handle the fragile glass fibers during the repair process. In addition, the use of spare fibers installed in vehicles such as an aircraft at the time of system installation can avoid any need to handle the fibers, if the method is applied correctly.
Another technique has been to have spare fibers running the entire distance run by the main fibers. In that approach, there has been no known way to protect the ends of the unused fibers. Accordingly, they are often damaged, and have to be cut back and cleaned before they can be terminated and used to replace a broken fiber. Additionally, the optic fibers have to be terminated at the time of use, which is a similar process to the 30-minute repair process mentioned above and requires special tools and training.
Yet another approach has been to have the spare fibers terminated and the termini contained in a safe environment until needed. However, for ribbon cables, it is awkward in application since the fibers are all grouped together in close proximity.
It has also been known to use automated reconfiguration approaches based on electromechanical switches. Such systems have several drawbacks, including extra weight, power consumption, large optical losses through the switches, and the need to positively lock the reconfiguration system in its proper state during flight.
As can be seen, there is a need for a manual optical cable reconfiguration or rearrangement of systems that avoids the above problems. The rearrangement of the connections should be done in as simple and robust a system as possible, with a minimum of special tools, cleaning, or training required. The reconfiguration should allow optical connections to be rearranged manually at an existing maintenance point. It should not require any direct handling of the optical fiber, nor should it require any electricity. It should make use of simple optical components and manufacturing techniques commonly known in industry. Another factor involved is cost savings.
In one aspect of the present invention, an optical cable splice includes at least one input line; a plurality of output lines; a plurality of connecting elements of substantially cubic shape, including at least one ninety degree turning cube and a plurality of straight through cubes, each of the connecting elements has a first surface disposed to be coupled to an end of at least one input line and at least two surfaces disposed to be respectively coupled to at least two output lines, whereby each input line defines an optic path for optic signals using one of the plurality of output lines; and at least one storage location for storing at least one connecting element not in use.
In another aspect of the present invention, an optic cable system has a first device; a second device; and a coupling subsystem coupling the first device and the second device, with the subsystem including a reconfigurable splice having a first end disposed to accommodate a first number of optic fibers coupled to the first device and a second end disposed to accommodate a second number of optic fibers coupled to the second device, wherein the first number has a lesser value than the second number, which has a plurality of input lines equal in number with the first number of optic fibers; a plurality of output lines equal in number with the second number of optic fibers; a plurality of connecting elements of substantially cubic shape including at least one ninety degree turning cube and a plurality of straight through cubes, each of the connecting element has a first surface disposed to be coupled to an end of the plurality of input lines and having at least two surfaces disposed to be coupled to at least two output lines respectively, whereby each input line defines an optic path for optic signals using one of the plurality of output lines; and at least one storage location for storing at least one connecting element not in use.
In still another aspect of the present invention, there is disclosed an aircraft optic cable system which includes an initial segment easily accessed for maintenance. The initial segment includes a first device; and a reconfigurable optical splice coupled to the first device. The optical splice has a first end disposed to accommodate a first number of optic fibers coupled to the first device and a second end disposed to accommodate a second number of optic fibers coupled to the second device, wherein the first number has a lesser numerical value than the second number; a plurality of input lines equal in number with the first number of optic fibers; a plurality of output lines equal in number with the second number of optic fibers; a plurality of connecting elements of substantially cubic shape including at least one ninety degree turning cube and a plurality of straight through cubes, each of the connecting elements has a first surface disposed to be coupled to an end of the plurality of input lines and having at least two surfaces disposed to be coupled to at least two output lines respectively, whereby each input line defines an optic path for optic signals using one of the plurality of output lines; at least one storage location for storing at least one connecting element not in use; and an intermediate segment not easily accessed by the maintainer. The intermediate segment has ribbon cables having a first end coupled to the plurality of output lines and spaced apart from the plurality of input lines, and a first portion of a set of discrete cables coupled to a second end of the ribbon cables disposed to fan-out to various locations. The system includes a final segment easily accessed for maintenance. The final segment includes a second device, and a second portion of the set of discrete cables interposed between the second device and the ribbon cables.
In yet still another aspect of the present invention, there is disclosed a method for configuring an optical cable splice which includes the steps of determining whether configuring is needed; opening a cover of the optical cable splice; and rearranging elements within the optical cable splice, whereby an incoming signal coming from an incoming cable is redirected from a first output cable to a second output cable.
As can be appreciated, this invention addresses a need for using fiber optics because of its high bandwidth and high density of signals achievable in connectors. The high density will be used to bring optical signals out of enclosures through small connectors for ribbon cables. However, in most cases, it is not desirable to take all the fibers in the ribbon from one location to another. It is necessary to xe2x80x9cfan-outxe2x80x9d the fibers so that the cable can branch and reach different locations. Therefore, in a vehicle such as an aircraft, a number of ribbon cables may be installed deep inside the aircraft, whereas at both ends of the cable system, one can use ribbon cables that may be easily changed or single fibers that can be easily exchanged. By way of an example, the cables may be used in the avionics bays leading to a number of locations in the peripherals of an airplane.